*{
    margin: 0;
    padding: 0;
}
.box{
    margin-top: 100px;
    display: flex;
}
.left ul{
    list-style: none;
    display: none;
}
li{
    border: 1px solid gray;
}
.right{
    border: 1px solid gray;
    flex: 1;
    display: flex;
    flex-wrap: wrap;
}
.right div{
    height: 100px;
    width: 300px;
    background: lightgreen;
    margin: 10px;
    
}